projects / ceph.git / blame
| Commit | Line | Data |
|---|---|---|
| 7c673cae FG |
1 | <html> |
| 2 | <head> | |
| 3 | <meta http-equiv="Content-Type" content="text/html; charset=US-ASCII"> | |
| 4 | <title>declval</title> | |
| 5 | <link rel="stylesheet" href="../../../../../../doc/src/boostbook.css" type="text/css"> | |
| 6 | <meta name="generator" content="DocBook XSL Stylesheets V1.77.1"> | |
| 7 | <link rel="home" href="../../index.html" title="Chapter 1. Boost.TypeTraits"> | |
| 8 | <link rel="up" href="../reference.html" title="Alphabetical Reference"> | |
| 9 | <link rel="prev" href="decay.html" title="decay"> | |
| 10 | <link rel="next" href="extent.html" title="extent"> | |
| 11 | </head> | |
| 12 | <body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> | |
| 13 | <table cellpadding="2" width="100%"><tr> | |
| 14 | <td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../../../../boost.png"></td> | |
| 15 | <td align="center"><a href="../../../../../../index.html">Home</a></td> | |
| 16 | <td align="center"><a href="../../../../../../libs/libraries.htm">Libraries</a></td> | |
| 17 | <td align="center"><a href="http://www.boost.org/users/people.html">People</a></td> | |
| 18 | <td align="center"><a href="http://www.boost.org/users/faq.html">FAQ</a></td> | |
| 19 | <td align="center"><a href="../../../../../../more/index.htm">More</a></td> | |
| 20 | </tr></table> | |
| 21 | <hr> | |
| 22 | <div class="spirit-nav"> | |
| 23 | <a accesskey="p" href="decay.html"><img src="../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../reference.html"><img src="../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../index.html"><img src="../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="extent.html"><img src="../../../../../../doc/src/images/next.png" alt="Next"></a> | |
| 24 | </div> | |
| 25 | <div class="section"> | |
| 26 | <div class="titlepage"><div><div><h3 class="title"> | |
| 27 | <a name="boost_typetraits.reference.declval"></a><a class="link" href="declval.html" title="declval">declval</a> | |
| 28 | </h3></div></div></div> | |
| 29 | <pre class="programlisting"><span class="keyword">template</span> <span class="special"><</span><span class="keyword">class</span> <span class="identifier">T</span><span class="special">></span> | |
| 30 | <span class="keyword">typename</span> <span class="identifier">add_rvalue_reference</span><span class="special"><</span><span class="identifier">T</span><span class="special">>::</span><span class="identifier">type</span> <span class="identifier">declval</span><span class="special">()</span> <span class="keyword">noexcept</span><span class="special">;</span> <span class="comment">// as unevaluated operand</span> | |
| 31 | </pre> | |
| 32 | <p> | |
| 33 | <span class="bold"><strong>C++ Standard Reference:</strong></span> C++11 20.2.4 [declval]. | |
| 34 | </p> | |
| 35 | <p> | |
| 36 | <span class="bold"><strong>Header:</strong></span> <code class="computeroutput"> <span class="preprocessor">#include</span> | |
| 37 | <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">type_traits</span><span class="special">/</span><span class="identifier">declval</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span></code> | |
| 38 | or <code class="computeroutput"> <span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">type_traits</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span></code> | |
| 39 | </p> | |
| 40 | <p> | |
| 41 | The function template <code class="computeroutput"><span class="identifier">declval</span></code> | |
| 42 | is used when a value of a certain type is required in a type computation | |
| 43 | context. For example, the type of the result of adding an <code class="computeroutput"><span class="keyword">int</span></code> | |
| 44 | and a <code class="computeroutput"><span class="keyword">float</span></code> can be obtained | |
| 45 | with the expression <code class="computeroutput"><span class="keyword">decltype</span><span class="special">(</span> <span class="identifier">declval</span><span class="special"><</span><span class="keyword">int</span><span class="special">>()</span> | |
| 46 | <span class="special">+</span> <span class="identifier">declval</span><span class="special"><</span><span class="keyword">float</span><span class="special">>()</span> <span class="special">)</span></code>. | |
| 47 | </p> | |
| 48 | </div> | |
| 49 | <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> | |
| 50 | <td align="left"></td> | |
| 51 | <td align="right"><div class="copyright-footer">Copyright © 2000, 2011 Adobe Systems Inc, David Abrahams, | |
| 52 | Frederic Bron, Steve Cleary, Beman Dawes, Aleksey Gurtovoy, Howard Hinnant, | |
| 53 | Jesse Jones, Mat Marcus, Itay Maman, John Maddock, Alexander Nasonov, Thorsten | |
| 54 | Ottosen, Roman Perepelitsa, Robert Ramey, Jeremy Siek, Robert Stewart and Steven | |
| 55 | Watanabe<p> | |
| 56 | Distributed under the Boost Software License, Version 1.0. (See accompanying | |
| 57 | file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>) | |
| 58 | </p> | |
| 59 | </div></td> | |
| 60 | </tr></table> | |
| 61 | <hr> | |
| 62 | <div class="spirit-nav"> | |
| 63 | <a accesskey="p" href="decay.html"><img src="../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../reference.html"><img src="../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../index.html"><img src="../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="extent.html"><img src="../../../../../../doc/src/images/next.png" alt="Next"></a> | |
| 64 | </div> | |
| 65 | </body> | |
| 66 | </html> |